PC, or personal computer, is a multi-purpose computer built to be used by an end-user. Starting in mid 1970s with Xerox Alto, PC has significantly improved over the three decades. Since the late 1980s, Microsoft operating systems and Intel hardware have dominated much of the personal computer market, first with DOS and then with Windows. Alternatives to Microsoft's Windows operating systems occupy a minority share of the industry. These include Apple's macOS and free open-source Unix-like operating systems such as Linux, AmigaOS and Chrome OS.